fn cset {|c t f|
  if $c {
    put $t
  } else {
    put $f
  }
}

fn mset {|c t f|
  all (cset $c $t $f)
}

fn call {|c t f @argv|
  var v = (cset $c $t $f)
  if (is (kind-of $v) fn) {
    $v $@argv
  } else {
    put $v
  }
}